Issue with storing data within an Array - Swift - arrays

Question

I currently have my set-up as followed:
I am running a query in Firebase to extract all of the genres within an array of genres, like so:
var genresLabelIndex : [String] = ["Horror", "Fiction", "Romance"]
Then I am creating a blank arrays for each of the genres to be able to store the information of the genres within each of the areas like so:
var horrorData = [InformationForFeed]()
var fictionData = [InformationForFeed]()
var romanceData = [InformationForFeed]()
InformationForFeed looks like so:
class InformationForFeed {
fileprivate var _uploadKey:String!
fileprivate var _userKey:String!
fileprivate var _imageURL:String!
fileprivate var _socialMedia:[String]
var uploadKey:String!{
return _uploadKey
}
var userKey:String!{
return _userKey
}
var imageURL:String!{
return _imageURL
}
init(dictionary:Dictionary<String,AnyObject>, socials: [String]) {
_socialMedia = socials
if let uploadKey = dictionary["upload_key"] as? String {
self._uploadKey = uploadKey
}
if let userKey = dictionary["user_key"] as? String {
self._userKey = userKey
}
if let imageURL = dictionary["imageUrl"] as? String {
self._imageURL = imageURL
}
}
}
I am then creating an Array of the list of genres arrays like so:
1) First I am creating an empty array of arrays like this:
var genreArrayIndex : [[InformationForFeed]] = []
2) Then within my init() of the UIView I am setting what will be in the array like this:
genreArrayIndex = [self.horrorData, self.fictionData, self.romanceData]
I then will run a function called getData() that will run my query and start storing the information.
I store my information of each genre in a tempArray, and then I set the genreArrayIndex[index] to equal the tempArray and then clear the tempArray as seen in getData below.
func getData() {
for genre in genresLabelIndex {
let dbReference = Database.database().reference().child("genres").child(genre)
let query = dbReference.queryLimited(toLast: 6)
query.observeSingleEvent(of: .value, with: { (snapshot : DataSnapshot) in
if snapshot.childrenCount > 0 {
for s in snapshot.children.allObjects as! [DataSnapshot] {
let item = s.value as! Dictionary<String,AnyObject?>
let facebook = (s.childSnapshot(forPath: "social_links").value as? NSDictionary)?["facebook_link"]
let audible = (s.childSnapshot(forPath: "social_links").value as? NSDictionary)?["audible_link"]
let amazon = (s.childSnapshot(forPath: "social_links").value as? NSDictionary)?["amazon_link"]
var socialsArray = [String]()
if facebook != nil {
socialsArray.append(facebook! as! String)
} else {
socialsArray.append("nil")
}
if audible != nil {
socialsArray.append(audible! as! String)
} else {
socialsArray.append("nil")
}
if amazon != nil {
socialsArray.append(amazon! as! String)
} else {
socialsArray.append("nil")
}
let data = InformationForFeed(dictionary: item as Dictionary<String,AnyObject>, socials: socialsArray)
self.newArray.append(data)
}
}
self.genreArrayIndex[self.genreArrayIndexCount] = self.newArray
self.genreArrayIndexCount = self.genreArrayIndexCount + 1
self.newArray.removeAll()
self.internalIndex = self.internalIndex + 1
if self.internalIndex == self.genresLabelIndex.count {
self.tableView.reloadData()
}
})
}
}
My tempArray looks like this:
var newArray = [InformationForFeed]()
The index looks like this:
var genreArrayIndexCount : Int = 0
Now comes the issue....
All of the information is properly being stored in the genreArrayIndex .....but... it is not actually storing the information in the arrays that being stored in genreArrayIndex.
So in other words if you were to print(self.genreArrayIndex) it would be fully populated. But if you were to print(self.fictionData) it would be blank.
How can I resolve this?

Answer 1

Array is a value type. That means its contents are copies. Initializing genreArrayIndex with empty horrorData, (and others) and then filling it with getData() does not also copy the data back into horrorData. I would recommend eliminating
genreArrayIndex = [self.horrorData, self.fictionData, self.romanceData]
and replacing horrorData, fictionData, ... with computed properties. Perhaps like this.
var horrorData: [InformationFeed] {
return genreArrayIndex[0]
}